1. Field of the Invention
Embodiments of the present invention generally relate to data protection systems and, more particularly, to a method and apparatus for providing point-in-time consistent backup images while reducing computing overhead.
2. Description of the Related Art
In a computing environment that hosts critical applications, data (e.g., financial data, user data, application data and the like) is backed up on a regular basis. As the amount of data to be backed up grows rapidly, there is a risk to overburden a computer while backing up such huge amount of data. As a result a backup window is considerably large. The backup window may be large due to large amount of data and/or frequent writes in the application that leads to higher number of copy-on-write (COW) operations. Generally, a copy-on-write operation requires one or more steps to be performed for each new write of a data block, which results in a significant amount of computing overhead, especially for large data systems. Consequently, a significant number of copy-on-write operations adversely affect the performance of the computing environment.
Current backup techniques perform a full backup process or an incremental backup process on a volume. As the backup process takes several hours during which one or more data blocks that are backed up may be changed. Consequently, the data blocks being backed up are not all point-in-time consistent since a particular data block may be changed during the backup process. For example, an applicant may write to a data block in the volume after an old version of the data block is backed up. As a result, the data block is not point-in-time consistent with the rest of the backed up data blocks. Consequently, the old version cannot be used to recovery data at any recovery point after the completion of the backup process.
In addition, snapshot based backup techniques takes a snapshot and then back up the data blocks. But, a first write of every block in the original volume suffer from the overhead associated with a copy-on-write operation. If the length of the backup window is large and/or there are frequent writes on the original volume then there may be a larger number of copy-on-write operations. Hence, larger number of copy-on-write operations results in overburdening the business server.
Accordingly, there is a need in the art for a method and apparatus for providing a backup image that is point-in-time consistent while reducing a computing overhead associated with copy-on-write operations for snapshot images.